Tools having locking adjustments

ABSTRACT

A tool, in particular a G-clamp, having a fixed clamping face on one end of an elongate body member and a further abutment face mounted on a slide member movable along the body member, the abutment face being movable relative to the slide member, and the slide member being capable of being slid along the body member to give quick-setting of the initial spacing between the clamping and abutment faces, subsequent pressure on said latter face effecting locking of the slide member on the support member.

United States Patent 1191 1111 3,

Bolton Oct. 28, 1975 TOOLS HAVING LOCKING ADJUSTMENTS 2,550,424 4/1951Penn 24/263 PJ x nv o Robert enjamin Bolton 14 Middle 3,383,101 5/1968Albert 24/263 F] X Drive, Ponteland, England FOREIGN PATENTS ORAPPLICATIONS 22 Filed: Feb. 7 75,695 6/1961 France 269/189 83,349 5/1920Switzerland 81/158 [21] Appl. No.: 440,869 334,157 8/1930 United Kingdom24/263 PJ Prima Examiner-Donald A. Griffin 52 user. 24 26 P-811 171. 1 Il 3 l g Attorney, Agent, or Firm--Larson, Taylor & I-lmds [51] Int. Cl.A44B 21/00; 8253 1/02; 8258 5/02 [58] Field of Search..,.. 24/263 PJ,263 LL, 263 LS, [57] ABSTRACT 24/263 263 134 249 PP; 81/175 A tool, inparticular a G-clamp, having a fixed clamp- 176, 157, 158; 269/189,203-205, 171.5, 16 ing face on one end of an elongate body member and afurther abutment face mounted on a slide member [56] References Cltedmovable along the body member, the abutment face UNITED STATES PATENTSbeing movable relative to the slide member, and the 640,500 1/1900Taylor 269/189 x Slide member being Capable of being slid along the983,148 1/ 1911 Krumhaar et a1... 269/ 189 X body member to givequick-setting of the initial spac- 1,187,109 6/1916 Steuernagel 269/204ing between the clamping and abutment faces, subse- ,753 4/1923 Otto etal.... 269/ 189 quent pressure on said latter face effecting locking of1,741,923 12/1929 Dohnal 269/l7l.5 the slide member on the Supportmember 1,929,539 10/1933 Steuernagcl 269/l71.5 2,461,687 2/1949 Hopfeld24/263 PJ UX 10 Claims, 3 Drawing Figures U.S. Patent' 0a. 28, 1975Sheet 1 of 2 3,914,830

US. Patent Oct. 28, 1975 Sheet20f2 3,914,830

TOOLS HAVING LOCKING ADJUSTMENTS The present invention relates to toolshaving locking adjustment and, inparticular to G-clamps although it maybe applied to any tool where a force-applying slide member is to have anadjustable position on a substantially rigid support member before forceis applied, it being necessary to lock the force-applying member inposition relative to the support member when force is being applied.

Most known G-clamps include a rigid support member provided with a fixedposition clamping face and an adjustable member carrying an abutmentface movable towards and away from the fixed clamping face. Theadjustable abutment faceis formed on one end of a threaded stemextending through a correspondingly threaded bore in the support member,the stem being provided at its other end with means for rotationthereof.

These known clamps have the disadvantage that adjustment of the clampopening is provided for wholly by rotation of the threadedstem and suchadjustment is a slow operation.

According to the present invention I provide a tool comprising a supportmember with rectangular crosssection having opposed first and secondsurfaces, a slide member mounted on the support member, the slide memberhaving a body portion which embraces the support member and a trappingsurface adjacent the first surface of the support member, a jammingmember pivotally mounted on the slide member, resilient meansurging thejamming member in one rotational direction against the second surface ofthe support member a stop on the slide member to limit the movement ofthe jamming member in the other rotational direction, and an abutmentface for contacting a workpiece or item 'to which force is to beapplied, this abutment face being mounted on the jamming member andbeing movable relatively to the slide member, the arrangement beingsuc'hthat pressure on the abutment face further urges the jamming member inthe one rotational direction to cause increased pressure of said memberagainst the second surface of the support member, said member thus beinggripped between the jamming member and said trapping surface to lock theslide member to the support member, the jamming member being releasablefrom the support member by pivoting movement of said jamming member andabutment face in the other rotational direction whereby the slide memberis slidable in either direction relative to the support member.

Preferably the jamming member includes an arcuate cam surface adapted topress against the second surface of the support member, the abutmentface being to the side of the pivot remote from said cam surface,whereby pressure on said abutment face rotates the jamming member in theone direction to bring an increased-diameter portion of said cam surfaceinto contact with the second surface of the support member toeffect'said locking.

Conveniently the abutment face is formed at one end -of an externallythreaded shaft mounted in a threaded bore in the jamming member.

ment surface. Said springmay be sufficiently light to allow the slidemember to be pushed by hand along the support member in a directionopposed to that of the force to be applied to the abutment face. Thethreaded shaft however constitutes a convenient lever for pivoting thejamming member in the other rotational direction about its pivot againstthe bias of the spring thereby to permit ready sliding movement of theslide member in either direction relative to the support member.

Thus the invention provides a tool, for example a clamping tool,permitting quick-setting of the clamping opening during initialengagement of a workpiece or item to be gripped, and which is such thatthe greater the clamping pressure on the item the greater is the lockingeffect of the mechanism.

An embodiment of the present invention will now be described, by way ofexample only, with reference to the accompanying drawings, wherein:

FIG. 1 is a side view of part of a G-clamp having a slidableforce-applying member adjustably mounted on a support member inaccordance with this invention;

FIG. 2 is a vertical section along the line 11- of FIG. 1, and

FIG. 3 is a vertical section along the line III-III of FIG. 2.

Referring to the drawings a G-clamp 1 has a substantially rigid supportmember in the form of a metal rod 2 of rectangular cross-section havingan abutment surface 2a. A head member 3 is fixed to one end of the rod2, conveniently by means of bolts or spring dowels. A slide member 4 ismounted on the rod 2 and is slidable along the rod so that a clampinghead 5 can be brought towards the head member 3 to grip an item betweenthem.

The slide member 4 has a generally cylindrical portion 6 of rectangularcross-section that engages the rod 2. In one embodiment of the inventiona pair of pins or bolts (not shown) are fixed at the end of the rod 2opposite the head member 3 and project from the sides of the rod toprevent the member 4 being slid off the rod, the pins or bolts engagingrecesses 20 in the member 4.

A pair of lugs 7, integrally formed with the portion 6, provide bearingsupport for a pivot 8 carrying a jamming member 9 having an internallythreaded bore 10. An externally threaded shaft 1 1 screws into the bore10 and carries the clamping head 5 at one of its ends. The clamping headis mounted on the shaft 11 by means of a ball-joint 12 so that, over alarge range of angular positions of the bore 10 about the pivot 8, theclamping head 5 can grip an item by contact over its abutment face 13. Atransverse handle 14 is provided in a bore 15 in the end of the shaft 11remote from the clamping head 5.

A coil spring 16 is provided in a blind recess 17 in the member 9 andbears on a face 18 of the member 4 to exert a pivoting moment biassingthe jamming member 9 onto the rod 2.

The jamming member 9 contacts the abutment surface 2a of the rod 2 witha hardened, curved portion 21 whose radius relative to the pivot 8increases anticlockwise in the plane of its pivoting movement so that anincreasing clockwise moment exerted on the jamming member 9 provides anincreasing pressure between the jamming member and the rod 2. The curvedportion 21 is serrated, the transverse section through each tooth beingslightly V-shaped (for example of the order of 3 from the horizontal) asseen in FIG. 2 thus ensuring that the jamming member 9 engages with thecentral region of the associated surface 2a of the rod 2 therebydecreasing the possibility of deformation of said surface 2a of the rod2 that full face contact of the teeth with the rod might cause. Atrapping surface 22 of the portion 6 lies adjacent the lower surface ofthe rod 2 and co-acts with the jamming member to grip the rod.

The strength of the spring 16 may be such as to permit, when the G-clampis to grip an item between the head member 3 and the clamping head 5, aquick-set movement of the slide member 4 merely by pushing it to slidethe rod 2 towards the head member 3, the jamming member pivotingslightly against the relatively weak bias of the spring as the slidingoccurs. The spring 16 may be such as to exert a relatively largeclockwise moment on the jamming member to make simple pushing of themember 4 along the rod towards the head member 3 difficult. The jammingmember 9 can then be disengaged from the rod 2 by applying ananticlockwise moment to the jamming member about its pivot 8 using theshaft 11 as a lever, the top end of the face 18 of the slide memberacting as a stop to limit the counterclockwise movement of the jammingmember; this position of the jamming member 19 permits ready slidingmovement of the member 4 along the rod 2. Similarly, whatever strengthspring 16 is used, said disengagement using the shaft 11 as a leverpermits sliding movement of the clamping head away from the fixed headmember 3. It is preferred that the spring 16 is at least strong enoughto hold the member 4 in position on the rod against the weight of themember 4.

Subsequent to the quick-set movement of the member 4, the item can begripped by rotating the shaft 11 using the handle 14 so that theclamping head is translated towards the head member 3. The reaction tothe gripping force of the clamping head 5 produces a clockwise moment onthe jamming member 9, locking the member 4 in position on the rod. Thegreater the gripping force exerted by the clamping head the greater isthe normal reaction of the jamming member on the rod giving a greaterfrictional force opposing movement of the member 4 relative to the rod2.

In an alternative embodiment of the invention, the slide member 4 andits associated components can be slid off the end of the rod 2. In orderto prevent possible loss of the spring 16 from this unit when off thetool, a stop member is formed on the jamming member adjacent the lowerright hand region thereof, as viewed in FIGS. 1 and 3, and adapted toabut the adjacent sidewall of the member 4 thereby to prevent clockwiserotation of the jamming member 9 into the slide member 4. The spring 16cannot then completely disengage with the surface 18 of the member 4 andcannot therefore fall out of its recess 17. Clearly the location of thestop member is such as not to come into effect during normal operationof the tool. Such removability enables the member 4 to be turned through180 on the rod 2 and the tool to be used to provide a spacing orstretching action.

It is to be understood that while the rod 2 has been described as beingof rectangular cross-section it could be of round or any othercross-section which provides the rod with sufficient rigidity.

It has been found that the G-clamp described above, which can bemodified in various ways, is a versatile and reliable tool which can beused to give quick-set movement and high gripping pressures.

What I claim and desire to protect by Letters Patent is:

l. A tool comprising a support member with rectangular cross section,opposed first and second surfaces on said support member, a slide membermounted on the support member, a body portion which forms part of saidslide member and which embraces said support member to allow freesliding movement between them, a trapping surface on said slide memberlying adjacent said first surface of the support member, a jammingmember pivotally mounted on the slide member, resilient means urging thejamming member in one rotational direction against the second surface ofthe support member, a stop on the slide member to limit the movement ofthe jamming member in the other rotational direction, and an abutmentface for contacting a workpiece or item to which force is to be applied,this abutment face being mounted on the jamming member and being movablerelatively to the slide member, the arrangement being such that pressureon the abutment face further urges the jamming member in the onerotational direction to cause increased pressure of said member againstthe second surface of the support member, said support member thus beinggripped between the jamming member and said trapping surface to lock theslide member to the support member, the jamming member being releasablefrom the support member by pivoting movement of said jamming member andabutment face in the said other rotational direction whereby the slidemember is slidable in either direction relative to the support member.

2. A tool as claimed in claim 1 in which the jamming member includes anarcuate cam surface adapted to press against the second surface of thesupport member, the abutment face being to the side of the pivot remotefrom said cam surface, whereby pressure on said abutment face rotatesthe jamming member in the one direction to bring an increased-diameterportion of said cam surface into contact with the second surface of thesupport member to effect said locking.

3. A tool as claimed in claim 2 and including toothed serrations on thearcuate cam surface of the jamming member. I

4. A tool as claimed in claim 3 in which each tooth of the serrations issubstantially V-shaped in transverse section to give substantially pointcontact of each tooth with the second surface of the support member.

5. A tool as claimed in claim 2 in which the resilient means comprises acoil spring reacting between the slide member and a region on thejamming member to the same side of the pivot as the abutment face.

6. A tool as claimed in claim 5 and including an externally threadedshaft at one end of which is formed said abutment face, the jammingmember defining therein a correspondingly threaded bore in which saidshaft is mounted.

7. A tool as claimed in claim 6 in which a clamping face is carried atone end of the support member, said abutment face being adapted toco-operate with said clamping face to enable an item to be clampedtherebetween.

8. A tool as claimed in claim 1 in which the slide member, jammingmember, resilient means and abutment face comprise a unit which can beremoved from the support member and replaced on said support member inthe reverse direction, the slide member then being locked to the supportmember on application of section corresponding to said support memberand completely encompasses said rectangular support member, and isaxially spaced on said slide member from said jamming member so as toencompass said support member at locations axially removed from thelocations at which said jamming member contacts the support member.

1. A tool comprising a support member with rectangular cross section,opposed first and second surfaces on said support member, a slide membermounted on the support member, a body portion which forms part of saidslide member and which embraces said support member to allow freesliding movement between them, a trapping surface on said slide memberlying adjacent said first surface of the support member, a jammingmember pivotally mounted on the slide member, resilient means urging thejamming member in one rotational direction against the second surface ofthe support member, a stop on the slide member to limit the movement ofthe jamming member in the other rotational direction, and an abutmentface for contacting a workpiece or item to which force is to be applied,this abutment face being mounted on the jamming member and being movablerelatively to the slide member, the arrangement being such that pressureon the abutment face further urges the jamming member in the onerotational direction to cause increased pressure of said member againstthe second surface of the support member, said support member thus beinggripped between the jamming member and said trapping surface to lock theslide member to the support member, the jamming member being releasablefrom the support member by pivoting movement of said jamming member andabutment face in the said other rotational direction whereby the slidemember is slidable in either direction relative to the support member.2. A tool as claimed in claim 1 in which the jamming member includes anarcuate cam surface adapted to press against the second surface of thesupport member, the abutment face being to the side of the pivot remotefrom said cam surface, whereby pressure on said abutment face rotatesthe jamming member in the one direction to bring an increased-diameterportion of said cam surface into contact with the second surface of thesupport member to effect said locking.
 3. A tool as claimed in claim 2and including toothed serrations on the arcuate cam surface of thejamming member.
 4. A tool as claimed in claim 3 in which each tooth ofthe serrations is substantially V-shaped in transverse section to givesubstantially point contact of each tooth with the second surface of thesupport member.
 5. A tool as claimed in claim 2 in which the resilientmeans comprises a coil spring reacting between the slide member and aregion on the jamming member to the same side of the pivot as theabutment face.
 6. A tool as claimed in claim 5 and including anexternally threaded shaft at one end of which is formed said abutmentface, the jamming member defining therein a correspondingly threadedbore in which said shaft is mounted.
 7. A tool as claimed in claim 6 inwhich a clamping face is carried at one end of the support member, saidabutment face being adapted to co-operate with said clamping face toenable an item to be clamped therebetween.
 8. A tool as claimed in claim1 in which the slide member, jamming member, resilient means andabutment face comprise a unit which can be removed from the supportmember and replaced on said support member in the reverse direction, theslide member then being locked to the support member on application ofpressure on the abutment face in the reverse direction.
 9. A tool asclaimed in claim 1 wherein said body portion embraces enough of eachsurface of said rectangular support member as to support said slidemember thereon independently of any support contributed by said jammingmember.
 10. A tool as claimed in claim 9 wherein the interior of saidbody portion is of closed rectangular cross-section corresponding tosaid support member and completely encompasses said rectangular supportmember, and is axially spaced on said slide member from said jammingmember so as to encompass said support member at locations axiallyremoved from the locations at which said jamming member contacts thesupport member.